Bright rear lights

[mattheus]

Very pleased (and quietly chuffed) to help, TC.

The language in RVLR is "undue dazzle or discomfort". Some folks in wigs and gowns will doubtless earn a crust by pinning down "undue".

Sure, you could debate the exact definition of this. But the fact is that quite a few current lights cause discomfort to other road users (especially when flashing), and inhibit their ability to perceive other hazards. I recently passed a "well-lit" cyclist, and as I came alongside I could see nothing but red - no cyclist, no road ahead. Thanks mate.

This is clearly "too much light", however you choose to interpret the wording of the laws.

[irc]

Very pleased (and quietly chuffed) to help, TC.

The language in RVLR is "undue dazzle or discomfort". Some folks in wigs and gowns will doubtless earn a crust by pinning down "undue".

Sure, you could debate the exact definition of this. But the fact is that quite a few current lights cause discomfort to other road users (especially when flashing), and inhibit their ability to perceive other hazards. I recently passed a "well-lit" cyclist, and as I came alongside I could see nothing but red - no cyclist, no road ahead. Thanks mate.

This is clearly "too much light", however you choose to interpret the wording of the laws.

It's never happened to me. I'm frequently dazzled by brake lights on stationary cars, headlights from oncoming cars etc.

IMO the current generation of lights, Smart Superflash, Cateye LD610 etc are bright enough without overdong it. Some current lights marketed as 1W and so on may be going to far. I certainly still see far more bikes with inadequate rear lights than with good visible setups. I can't recall ever seeing one I thought uncomfortably bright.

[thirdcrank]

Particularly now that hi-level led third brake lights seem to be standard on all recent models of car, the potential for dazzling those behind is greater than you are likely to find on a pedal cycle. Pumping the brake pedal just puts the brass knobs on. And unnecessarily indicating - as when stationary in a dedicated turn lane - all adds to the discomfort of somebody sitting behind. I have a feeling that brake lights and indicators are automatically dimmed when the sidelights are turned on, but even so, the effect is still pretty bright.

Of course, nothing you could fit on a bike would approach the effect of undipped modern car headlights shining straight into your face.

OTOH, we have had posts from people with DIY rear lights who have made a big thing about how bright they are - I seem to remember the odd one saying it was a way of encouraging drivers to keep at a safe distance. Overall, it's something to be be aware of when positioning a rear light - you want the beam pointing level so it's seen from as far away as possible, rather than losing the effect by pointing at random, and there's nothing to be gained by having a light irritating somebody behind, either another cyclist in a group, or a queueing driver. And as what somebody else has called the lighting arms race winds up, it coosts nothing to think of others. IMO.

[mattheus]

...
I recently passed a "well-lit" cyclist, and as I came alongside I could see nothing but red - no cyclist, no road ahead. Thanks mate.

This is clearly "too much light", however you choose to interpret the wording of the laws.

It's never happened to me. I'm frequently dazzled by brake lights on stationary cars, headlights from oncoming cars etc.

IMO the current generation of lights, Smart Superflash, Cateye LD610 etc are bright enough without overdong it. Some current lights marketed as 1W and so on may be going to far. I certainly still see far more bikes with inadequate rear lights than with good visible setups. I can't recall ever seeing one I thought uncomfortably bright.

I should clarify that the above experience was a 1-off - that light was leagues of brightness ahead of other lights I've seen in the flesh. But the fact is they are out there, and technology isn't likely to go backwards. Have you seen the rear Dinottes? They only make any sense pointed at the ground to give a warm pool of red light. I suspect that any light with a run-time of [guess] 40hrs+ with mainstream batteries will not be too bright. The problem is that folks are fitting 1-night-wonders, either out of fear, or just to be at the front of the bling wave. [Off-road front lights are a big problem used onroad.]

I agree that the current mid-range lights are about right, and lots of riders are badly lit. But advances will move the distribution towards brighter lights, whilst a minority will _still_ ride unlit and be all the more vulnerable, as cars and bikes move to ever brighter lights. God help the pedestrians and wildlife!

[From the perspective of a social rider, even the current mid-range lights are a problem if they are angled above the horizontal - more common than you might think, especially when mounted to seat-stays.]

[gentlegreen]

My DIY "be seen in traffic" lights each have 3.5 watts' worth of LEDs. They give me confidence in thick fog.



They cast a near hemi-spherical beam and are ideal for being seen obliquely.
But I can switch to alternative lights if necessary that are deliberately less bright and more diffuse - though I haven't quite got the ergonomics of the switching right yet.

The most challenging situation would be if I was using an on-road cycle lane and wanted to be seen by traffic, but was being followed by another cyclist.

[mattheus]

Gentlegreen:
That looks the perfect tail-light for fog!

However, in that picture it looks a smidge brighter than car brake-lights. If so, I think it's too bright to use on unlit roads, or on lit roads with other bikes about.

We're into compromises and grey areas here - if you're riding with others, motorists are bound to take more notice of you (packs of 20 get huge respect in daytime, I've noticed!). And urban areas with high cyclist numbers tend to have drivers who are more aware - look at Oxford, where the ninjas are very rarely mown done, simply because motorists are looking out for them (mostly).

Cars have switchable fog lights - I think we have to take on similar responsibility if we want to 'compete' with their lights.

[mattheus]

Note also this useful stuff from CJ on the other bright rear lights thread:
viewtopic.php?f=5&t=44002#p356328

[BSRU]

I have a Dinotte 400R and it is angled downwards, illuminating the road surface in a large cone shape behind me.
It only annoys car drivers if the are within a a metre or two of my rear wheel, where they should not be anyway.

[gentlegreen]

I have a couple of 3 watt cold cathode fluorescents on order for my alternative front light.

The alternative rear light is at the prototype stage.

[BSRU]

I have a couple of 3 watt cold cathode fluorescents on order for my alternative front light.

The alternative rear light is at the prototype stage.

Are not fluorescents a little delicate for Britain's billiard smooth road network?

[gentlegreen]

Are not fluorescents a little delicate for Britain's billiard smooth road network?

We shall see.

My previous main front light bounced around on some very rough roads for over two years / 4,000 miles.

[thirdcrank]

[... even the current mid-range lights are a problem if they are angled above the horizontal - more common than you might think, especially when mounted to seat-stays.]

That's reminded me of an experience, last winter or possibly the one before, I was briefly on the wheel of a youthful local club cyclist. She had one of those long, slim Cateye rear lapms which has a lot of LEDS in a single row, with half a dozen switching modes. It was mounted on the offside seatstay so it ran parallel with it, very neat but not how it was meant to be used. Apart from losing a lot of its effect as a rear lamp, it was directed right in my eyes. Probably the most effective way of stopping somebody following your wheel that has been invented. As a very lazy rider by nature, I can follow a wheel pretty closely, but that certainly 'burned me off.' Only effective in a nocturne, I suppose.

[BSRU]

Are not fluorescents a little delicate for Britain's billiard smooth road network?

We shall see.

My previous main front light bounced around on some very rough roads for over two years / 4,000 miles.

If they can survive 4,000 miles on Britain's roads that sounds like they are very sturdy.
Do these fluorescents have the same mercury dust problem as standard CFL's?

[gentlegreen]

Do these fluorescents have the same mercury dust problem as standard CFL's?

They all contain about as much mercury as you could get from eating too many tuna sandwiches

If the lamp breaks when it's powered up, the mercury would escape as vapour. If the lamp was cold, it would presumably be in amalgam with the electrodes.

[Phil_Lee]

"Cycle lights mustn't dazzle" seems to be included in RVLR section 27, if I understand it correctly: http://www.legislation.gov.uk/uksi/1989 ... on/27/made

Doesn't this only apply to "the use of lamps other than those to which regulation 24 refers"?
Regulation 24 covers front and rear position lights, among others, so bicycle lights wouldn't seem to be covered by this limitation on use (maybe because any dazzle or discomfort is not "undue"?).

Not that I think it's a good idea to dazzle anyone - surely it could be argued to be lack of reasonable consideration for other road users, if nothing else.

I do think we are getting to the point where rear lighting is (or can be) powerful enough that it should probably be switchable while riding.